Many residences have a bathtub, and people often enjoy relaxing by taking a warm bath. A common issue with such activities is that the bath water tends to cool, sometimes rather quickly. Sitting in lukewarm water is not quite as enjoyable or therapeutic as a warm bath. To alleviate the cooling of bath water, people often simply add more hot water. Obviously this requires more water, and, unless water is drained, will change the water level in the bathtub.
There are a number of immersible water/fluid heaters on the market, however most are not suited for use in a bathtub while a person is using the bathtub (e.g. taking a bath). This is because of the risk of electric shock due to such devices being powered by standard household electric service (120+ volts AC). An alternative approach pumps water out of the bathtub through one pipe, into a separate unit containing a heating element, and the heated water is then returned through another pipe back into the bathtub. This approach removes the risk of electric shock, but is unnecessarily complex and risks spilling water outside the bathtub. Such devices are also not easy to clean.
Therefore, a need exists to overcome the problems with the prior art as discussed above.